Rheostat.



H. D. JAMES. RHEOSTAT. APPLICATION FILED JULY 17. 1905 Patented June 29, 1909.

INVENTOR ATTORNEY nutter n JAMIJs, or r rrfrseuno, rrsusvhvafsi 't a MANUFACTURING c runny; A con oaa'r Specification of Letters Patent.

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Patented June 29, 1909.

Application filed July 17, 1906. Serial No. 270,162.

To all whom it may concern:

Be itknown that I, HENRY D. JAMus, a citizen of the United States, and a resident of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful improvement in Rheostats, of which the following is a specification.

lVly invention relates to rheostats and particularly to devices of this general character .which are employed for the control of electric motors and for similar purposes,

The object of my invention is to provide a simple, compact and durable means for ell'ccting variations in the resistance of an electric circuit, and a further object of the invention is to provide means for reversing circuit connections by the movement of a single member that cooperates directly with the resistance elements.

in the accompanying drawing, Figure l is a diagrammatic viewof an electric motor and a rheostat embodying my invention. Fig. 2 is a side elevation of one 01"? the resistance grids utilized in my invention, and Fig. 3 is an end elevation of a plurality of the grids shown in Fig. 2.

As licro illustrated, my invention comprises two groups 1 and 2 of resistance elements, each of which comprises four sets of grids 3 arranged in pairs. Each grid 3 is n'el'erably in the lorm ol an iron casting of zigzag formation, as indicated in Fig. 2, the grids being so connected and insulated that those of each set shall be connected in series, as indicated in Figs. 1 and lroperly fastened to the outerends and clamped etween adjacent terminal por tions of the grids, are contact bars 4 of relatively good conducting material, having alincd outer surfaces 5 with which ongage the brushes (3 of movable contact devices 7, suitable blow-out coils 8 being pro vidcd, if desired. The devices 7 are meclnmicnlly connected. together but suitably insulated from each other by means of a l'ramc E), which may be operated by a suit- I nblc handle 10. The outer cnds ol the groups of' grids 3 are so conn cclcd lo the supply circuit ll--12 and lo the armatur and licld magnct winding 1'! ol a motor [5 that when the contact dcviccs are in engagcmcnt with the grid contact. lcrminals 5 of one group the motor will rotate in one dircction and when the contact devices are moved to engage with the contact terminals 5 of the other group the direction of the How of current through the armature will be reversed so that the direction of rotation of. the motor armature will be reversed. Obviously, the connections might be so arranged b7 amount of resistance 1n the group 1 ot. the

resistance elements is included in the motor circuit, and by moving the devices by means of the handle 10 toward the left, the resistance will be gradually cut out. ll. it is desired to reverse the motor, the contact mem bers 7 will be moved from left to right into engagement with the contact terminals 5 oi. the group 2 and the motor will then be reversed with all of the resistance of the group 2 in circuit, and this may be gradually cut. out by moving the contact mcn'ibers toward the ends of the grids which are connected to the motor and to the external circuit.

It will be undcrstomlv that this specific arrangement of resistance clcn'ients and the structure of the contact devices, in so far as structural features are shown, are merely indicative of any suitable arrangcmcnt and means for c'l'i'ccting the desired rcsult and that any suitable means, whereby substantially the same mode oi operation and results are secured, is within the scope of my invention.

I claimas my invention:

l/lho combination with two groups of resistance grids provided with angular contact terminals clamped between them, and a motor to which said grids are permanently connected, of movable contact devices for engaging either group of grid contact tennis nals and for varying the number of grids included in. the motor circuit.

2. The (.zombination with an electric motor and two groups ol resistance grids reversely conncclcd to one member of the motor and provided with contact lcrn'iinalsof better conductivity than the grids, of contact dcviccs lor engaging the one or the other group of grid contact terminals, according to the direction of motor rotation desired, and for varying the mu'nbcr of grids in circuit with the motor. 7 v

3. A. rhcostnt (Z()lll )l'lSIllg two groups oi 'ilO 5 for connecting either group of resistance ele- Witnesses:

resistance elenients disposed in rectilinear In testimony whereof, I have hereunto ailinenient with each other and having their subscribed my name this 11th day of July,

router ends reversely connected to a translat- 1905. ing device, and reciprocatory contact devices HENRY D. JAMES.

ments in circuit and for varying the number Ross W. COPELAND, of active elements. BIRNEY HINES. 

